How to use Gossip with mDNS only?

[cocoon]

In short:
I want to to and tried to use Gossip with mDNS Lookup in local network only.
But it never received something that was broadcasted. (even on the same host)

I am coming from using swarm-discovery (https://github.com/rkuhn/swarm-discovery) before directly and used attributes to distribute data. Later I came across iroh and thought, oh it says it offers more, easier out of the box.
I had looked around, also distributed topic tracker, GuardianDB would fit perfectly, but all rely on external services.
I got working with spawning a local DHT server in code and add the local address, but that is only working on the same host then.

I guess it is not working out of the box with mDNS, and reading this example makes me think, I might need to handle something still on my own?
https://github.com/n0-computer/iroh/blob/v0.98.1/iroh/examples/mdns_address_lookup.rs

An Gossip example with mDNS (LAN) only would be nice.

[matheus23]

When you say "I tried to use Gossip with mDNS Lookup", I assume you're referring to trying to use iroh-gossip and you're configuring your iroh endpoint with MdnsAddressLookup, is that right?

[cocoon]

Yes, like:

let mdns = iroh::address_lookup::mdns::MdnsAddressLookup::builder();
...
 let mut builder = Endpoint::builder(LocalDiscoveryPreset)
            .secret_key(secret_key.clone())
            .address_lookup(mdns)
            .relay_mode(RelayMode::Disabled);
...

let gossip = Gossip::builder().spawn(endpoint.clone());

let router = Router::builder(endpoint.clone())
            .accept(iroh_gossip::ALPN, gossip.clone())
            .spawn();
...
let bootstrap: Vec<EndpointId> = Vec::new();
let subscription = gossip.subscribe(topic.clone(), bootstrap).await?;
let (sender, receiver) = subscription.split();

(currently last changed to distributed topic tracker, old line commented)

pub async fn broadcast_update(&self, update: &DeviceUpdate) -> anyhow::Result<()> {
        println!("➡️ SENDING BROADCAST: {:?}", update);

        let json = serde_json::to_vec(update)?;
        let bytes = Bytes::from(json);

        //self.sender.broadcast(bytes).await?; //iroh-gossip
        self.sender.broadcast(bytes.to_vec()).await?; // Distributed Topic Tracker

        println!("✔️ BROADCAST SENT!");

        Ok(())
    }

 tokio::spawn(async move {
        println!("Gossip listener started…");

        while let Some(event) = receiver.next().await {

            println!("GOSSIP EVENT: {:?}", event);
...

[cocoon]

Today I found something that seems to show what needs to be done.
It uses an old iroh version 0.35, but I migrated it to current 0.98.

It confirms for me that it is not working out of the box and needs to add custom handlers for peers:
https://github.com/therishidesai/iroh-gossip-discovery

update:
have it now working fully automated using mDNS broadcasts:
https://github.com/cocoon/iroh-gossip-discovery/blob/iroh_0.98/examples/address_book_demo.rs